Phylogeny and polyphasic taxonomy ofThe genus Caulobacter is composed of prosthecate bacteria often specialized for oligotrophic environments. The taxonomy of Caulobacter has relied primarily upon morphological criteria: a strain that visually appeared to be a member of the Caulobacter has generally been called one without challenge. A polyphasic approach, comprising 165 rDNA sequencing, profiling restriction fragments of 165-235 rDNA interspacer regions, lipid analysis, immunological profiling and salt tolerance characterizations, was used to clarify the taxonomy of 76 strains of the genera Caulobacter, Brevundimonas, Hyphomonas and Mycoplana. The described species of the genus Caulobacter formed a paraphyletic group with Caulobacter henricii, Caulobacter fusiformis, Caulobacter vibrioides and Mycoplana segnis (Caulobacter segnis com b. nov.) belonging to Caulobacter sensu stricto. Caulobacter bacteroides (Brevundimonas bacteroides comb. nov.), C. henricii subsp. aurantiacus (Brevundimonas aurantiaca comb. nov.), Caulobacter intermedius (Brevundimonas intermedia comb. nov.), Caulobacter subvibrioides (Brevundimonas subvibrioides com b. nov.), C. subvibrioides subsp. albus (Brevundimonas alba comb. nov.), Caulobacter variabilis (Brevundimonas variabilis comb. nov.) and Mycoplana bullata belong to the genus Brevundimonas. The halophilic species Caulobacter maris and Caulobacter halobacteroides are different from these two genera and form the genus Maricaulis gen. nov. with Maricaulis maris as the type species. Caulobacter leidyia was observed to cluster with species of the genus Sphingomonas. Caulobacter crescentus is synonymous with C. vibrioides and C. halobacteroides is synonymous with Maricaulis maris as determined by these analyses and DNA-DNA hybridization. Biomarkers discerning these different genera were determined. The necessary recombinations have been proposed and a description of Maricaulis is presented.
Biological air filters have been proposed as a cost-effective technology for reducing odor emissions from intensive swine production facilities. In this work we present results from the application of membrane inlet mass spectrometry (MIMS) for continuously monitoring the removal of odorous compounds in biological air filters. The sensitivity and selectivity were tested on synthetic samples of selected odorous compounds, and linearity and detection limits in the lower ppb range were demonstrated for all compounds tested (methanethiol, dimethyl sulfide, carboxylic acids, 4-methylphenol, aldehydes, indole, and skatole) except trimethylamine. The method was applied in situ at two full-scale filters installed at swine houses. The results have been compared with analyses by thermal desorption gas chromatography-mass spectrometry (TD-GC/MS), and odor was measured by olfactometry. By comparison with TD-GC/MS, observed MIMS signals were assigned to 4-methylphenol, 4-ethylphenol, indole, skatole, the sum of volatile reduced organic sulfur compounds (ROS), and three subgroups of carboxylic acids. The removal rates were observed to be related to air-water partitioning with removal efficiencies in the range of 0 to 50% for low-soluble organic sulfur compounds and high removal efficiencies (typically 80-100%) for more soluble phenols and carboxylic acids. Based on the results and published odor threshold values, it is estimated that the low removal efficiency of ROS is the main limitation for achieving a higher odor reduction.
Hospital wastewater contains high concentrations of pharmaceuticals, which pose risks to receiving waters. In this study, a pilot plant consisting of six moving bed biofilm reactors (MBBRs) in series (with the intention to integrate Biological Oxygen Demand (BOD) removal, nitrification and denitrification as well as prepolishing Chemical Oxygen Demand (COD) for ozonation) was built to integrate pharmaceutical removal and intermittent feeding of the latter reactors aimed for micropollutant removal. Based on the experimental resultss, nitrifying MBBRs achieved higher removal as compared to denitrifying MBBRs except for azithromycin, clarithromycin, diatrizoic acid, propranolol and trimethoprim. In the batch experiments, nitrifying MBBRs showed the ability to remove most of the analysed pharmaceuticals, with degradation rate constants ranging from 5.0 × 10 h to 2.6 h. In general, the highest degradation rate constants were observed in the nitrifying MBBRs while the latter MBBRs showed lower degradation rate constant. However, when the degradation rate constants were normalised to the respective biomass, the intermittently fed reactors presented the highest specific activity. Out of the 22 compounds studied, 17 compounds were removed with more than 20%.
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